1. Field of the Invention
The present invention relates to a multifunctional IC card having an electromagnetic wave protection means.
2. Description of the Related Art
A large number of multifunctional IC cards, such as memory cassettes, currently employ a housing made of a plastic material in consideration of cost or a request from a customer. The plastic housing does not shield an electromagnetic wave as well as metal case. However, no anti-electromagnetic wave countermeasure is usually taken. Furthermore, in a multifunctional IC card or an intelligent card incorporating a semiconductor device such as a CPU integrated circuit (IC) chip, electromagnetic wave noise is generated from clocks operating the CPU. This noise causes a disturbance in a device outside the card. However, no countermeasure against electromagnetic wave noise generated in a card comprising a CPU is taken.